darkkirb/old-cross-binutils
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Changed the @node to use INODE

Browse source
This commit is contained in:
Steve Chamberlain 1991-12-19 01:36:25 +00:00
parent 3d60de8161
commit 4a96bc044a
1 changed files with 425 additions and 337 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

762
bfd/section.c
View file

@ -18,14 +18,16 @@ You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
/*doc*
@section Sections
Sections are supported in BFD in @code{section.c}.
/*
SECTION
Sections
The raw data contained within a BFD is maintained through the section
abstraction. A single BFD may have any number of sections, and keeps
hold of them by pointing to the first, each one points to the next in
the list.
Sections are supported in BFD in <<section.c>>.
The raw data contained within a BFD is maintained through the
section abstraction. A single BFD may have any number of
sections, and keeps hold of them by pointing to the first,
each one points to the next in the list.
@menu
* Section Input::
@ -34,64 +36,73 @@ the list.
* section prototypes::
@end menu
@node Section Input, Section Output, Sections, Sections
@subsection Section Input
When a BFD is opened for reading, the section structures are created
and attached to the BFD.
INODE
Section Input, Section Output, Sections, Sections
Each section has a name which describes the section in the outside
world - for example, @code{a.out} would contain at least three
sections, called @code{.text}, @code{.data} and @code{.bss}.
SUBSECTION
Section Input
Sometimes a BFD will contain more than the 'natural' number of
sections. A back end may attach other sections containing constructor
data, or an application may add a section (using bfd_make_section) to
the sections attached to an already open BFD. For example, the linker
creates a supernumary section @code{COMMON} for each input file's BFD
to hold information about common storage.
When a BFD is opened for reading, the section structures are
created and attached to the BFD.
The raw data is not necessarily read in at the same time as the
section descriptor is created. Some targets may leave the data in
place until a @code{bfd_get_section_contents} call is made. Other back
ends may read in all the data at once - For example; an S-record file
has to be read once to determine the size of the data. An IEEE-695
file doesn't contain raw data in sections, but data and relocation
expressions intermixed, so the data area has to be parsed to get out
the data and relocations.
Each section has a name which describes the section in the
outside world - for example, <<a.out>> would contain at least
three sections, called <<.text>>, <<.data>> and <<.bss>>.
@node Section Output, typedef asection, Section Input, Sections
@subsection Section Output
To write a new object style BFD, the various sections to be written
have to be created. They are attached to the BFD in the same way as
input sections, data is written to the sections using
@code{bfd_set_section_contents}.
Sometimes a BFD will contain more than the 'natural' number of
sections. A back end may attach other sections containing
constructor data, or an application may add a section (using
bfd_make_section) to the sections attached to an already open
BFD. For example, the linker creates a supernumary section
<<COMMON>> for each input file's BFD to hold information about
common storage.
The linker uses the fields @code{output_section} and
@code{output_offset} to create an output file.
The raw data is not necessarily read in at the same time as
the section descriptor is created. Some targets may leave the
data in place until a <<bfd_get_section_contents>> call is
made. Other back ends may read in all the data at once - For
example; an S-record file has to be read once to determine the
size of the data. An IEEE-695 file doesn't contain raw data in
sections, but data and relocation expressions intermixed, so
the data area has to be parsed to get out the data and
relocations.
The data to be written comes from input sections attached to the
output sections. The output section structure can be considered a
filter for the input section, the output section determines the vma of
the output data and the name, but the input section determines the
offset into the output section of the data to be written.
INODE
Section Output, typedef asection, Section Input, Sections
Eg to create a section "O", starting at 0x100, 0x123 long, containing two
subsections, "A" at offset 0x0 (ie at vma 0x100) and "B" at offset
0x20 (ie at vma 0x120) the structures would look like:
SUBSECTION
Section Output
*+
To write a new object style BFD, the various sections to be
written have to be created. They are attached to the BFD in
the same way as input sections, data is written to the
sections using <<bfd_set_section_contents>>.
section name "A"
output_offset 0x00
size 0x20
output_section -----------> section name "O"
| vma 0x100
section name "B" | size 0x123
output_offset 0x20 |
size 0x103 |
output_section --------|
The linker uses the fields <<output_section>> and
<<output_offset>> to create an output file.
The data to be written comes from input sections attached to
the output sections. The output section structure can be
considered a filter for the input section, the output section
determines the vma of the output data and the name, but the
input section determines the offset into the output section of
the data to be written.
Eg to create a section "O", starting at 0x100, 0x123 long,
containing two subsections, "A" at offset 0x0 (ie at vma
0x100) and "B" at offset 0x20 (ie at vma 0x120) the structures
would look like:
| section name "A"
| output_offset 0x00
| size 0x20
| output_section -----------> section name "O"
| | vma 0x100
| section name "B" | size 0x123
| output_offset 0x20 |
| size 0x103 |
| output_section --------|
*-
*/
@ -100,213 +111,231 @@ subsections, "A" at offset 0x0 (ie at vma 0x100) and "B" at offset
#include "sysdep.h"
#include "libbfd.h"
/*
INODE
typedef asection, section prototypes, Section Output, Sections
SUBSECTION
typedef asection
/*doc*
@node typedef asection, section prototypes, Section Output, Sections
@subsection typedef asection
SUBSECTION
typedef asection
The shape of a section struct:
CODE_FRAGMENT
.
.typedef struct sec
.{
. {* The name of the section, the name isn't a copy, the pointer is
. the same as that passed to bfd_make_section. *}
.
. CONST char *name;
.
. {* The next section in the list belonging to the BFD, or NULL. *}
.
. struct sec *next;
.
. {* The field flags contains attributes of the section. Some of
. flags are read in from the object file, and some are
. synthesized from other information. *}
.
. flagword flags;
.
.#define SEC_NO_FLAGS 0x000
.
. {* Tells the OS to allocate space for this section when loaded.
. This would clear for a section containing debug information
. only. *}
.
.
.#define SEC_ALLOC 0x001
. {* Tells the OS to load the section from the file when loading.
. This would be clear for a .bss section *}
.
.#define SEC_LOAD 0x002
. {* The section contains data still to be relocated, so there will
. be some relocation information too. *}
.
.#define SEC_RELOC 0x004
.
. {* Obsolete ? *}
.
.#define SEC_BALIGN 0x008
.
. {* A signal to the OS that the section contains read only
. data. *}
.#define SEC_READONLY 0x010
.
. {* The section contains code only. *}
.
.#define SEC_CODE 0x020
.
. {* The section contains data only. *}
.
.#define SEC_DATA 0x040
.
. {* The section will reside in ROM. *}
.
.#define SEC_ROM 0x080
.
. {* The section contains constructor information. This section
. type is used by the linker to create lists of constructors and
. destructors used by <<g++>>. When a back end sees a symbol
. which should be used in a constructor list, it creates a new
. section for the type of name (eg <<__CTOR_LIST__>>), attaches
. the symbol to it and builds a relocation. To build the lists
. of constructors, all the linker has to to is catenate all the
. sections called <<__CTOR_LIST__>> and relocte the data
. contained within - exactly the operations it would peform on
. standard data. *}
.
.#define SEC_CONSTRUCTOR 0x100
.
. {* The section is a constuctor, and should be placed at the
. end of the . *}
.
.
.#define SEC_CONSTRUCTOR_TEXT 0x1100
.
.#define SEC_CONSTRUCTOR_DATA 0x2100
.
.#define SEC_CONSTRUCTOR_BSS 0x3100
.
.
. {* The section has contents - a bss section could be
. <<SEC_ALLOC>> | <<SEC_HAS_CONTENTS>>, a debug section could be
. <<SEC_HAS_CONTENTS>> *}
.
.#define SEC_HAS_CONTENTS 0x200
.
. {* An instruction to the linker not to output sections
. containing this flag even if they have information which
. would normally be written. *}
.
.#define SEC_NEVER_LOAD 0x400
.
. {* The base address of the section in the address space of the
. target. *}
.
. bfd_vma vma;
.
. {* The size of the section in bytes of the loaded section. This
. contains a value even if the section has no contents (eg, the
. size of <<.bss>>). *}
.
. bfd_size_type size;
.
. {* If this section is going to be output, then this value is the
. offset into the output section of the first byte in the input
. section. Eg, if this was going to start at the 100th byte in
. the output section, this value would be 100. *}
.
. bfd_vma output_offset;
.
. {* The output section through which to map on output. *}
.
. struct sec *output_section;
.
. {* The alignment requirement of the section, as an exponent - eg
. 3 aligns to 2^3 (or 8) *}
.
. unsigned int alignment_power;
.
. {* If an input section, a pointer to a vector of relocation
. records for the data in this section. *}
.
. struct reloc_cache_entry *relocation;
.
. {* If an output section, a pointer to a vector of pointers to
. relocation records for the data in this section. *}
.
. struct reloc_cache_entry **orelocation;
.
. {* The number of relocation records in one of the above *}
.
. unsigned reloc_count;
.
. {* Which section is it 0.nth *}
.
. int index;
.
. {* Information below is back end specific - and not always used
. or updated
.
. File position of section data *}
.
. file_ptr filepos;
.
. {* File position of relocation info *}
.
. file_ptr rel_filepos;
.
. {* File position of line data *}
.
. file_ptr line_filepos;
.
. {* Pointer to data for applications *}
.
. PTR userdata;
.
. struct lang_output_section *otheruserdata;
.
. {* Attached line number information *}
.
. alent *lineno;
.
. {* Number of line number records *}
.
. unsigned int lineno_count;
.
. {* When a section is being output, this value changes as more
. linenumbers are written out *}
.
. file_ptr moving_line_filepos;
.
. {* what the section number is in the target world *}
.
. unsigned int target_index;
.
. PTR used_by_bfd;
.
. {* If this is a constructor section then here is a list of the
. relocations created to relocate items within it. *}
.
. struct relent_chain *constructor_chain;
.
. {* The BFD which owns the section. *}
.
. bfd *owner;
.
.} asection ;
*/
/*proto*
The shape of a section struct:
/*
INODE
section prototypes, , typedef asection, Sections
*+++
SUBSECTION
section prototypes
$typedef struct sec {
These are the functions exported by the section handling part of
<<libbfd>.
*/
The name of the section, the name isn't a copy, the pointer is
the same as that passed to bfd_make_section.
/*
FUNCTION
bfd_get_section_by_name
$ CONST char *name;
SYNOPSIS
asection *bfd_get_section_by_name(bfd *abfd, CONST char *name);
The next section in the list belonging to the BFD, or NULL.
$ struct sec *next;
The field flags contains attributes of the section. Some of these
flags are read in from the object file, and some are synthesized from
other information.
$flagword flags;
$#define SEC_NO_FLAGS 0x000
Tells the OS to allocate space for this section when loaded.
This would clear for a section containing debug information only.
$#define SEC_ALLOC 0x001
Tells the OS to load the section from the file when loading.
This would be clear for a .bss section
$#define SEC_LOAD 0x002
The section contains data still to be relocated, so there will be some
relocation information too.
$#define SEC_RELOC 0x004
Obsolete ?
$#define SEC_BALIGN 0x008
A signal to the OS that the section contains read only data.
$#define SEC_READONLY 0x010
The section contains code only.
$#define SEC_CODE 0x020
The section contains data only.
$#define SEC_DATA 0x040
The section will reside in ROM.
$#define SEC_ROM 0x080
The section contains constructor information. This section type is
used by the linker to create lists of constructors and destructors
used by @code{g++}. When a back end sees a symbol which should be used
in a constructor list, it creates a new section for the type of name
(eg @code{__CTOR_LIST__}), attaches the symbol to it and builds a
relocation. To build the lists of constructors, all the linker has to
to is catenate all the sections called @code{__CTOR_LIST__} and
relocte the data contained within - exactly the operations it would
peform on standard data.
$#define SEC_CONSTRUCTOR 0x100
The section is a constuctor, and should be placed at the end of the ..
$#define SEC_CONSTRUCTOR_TEXT 0x1100
$#define SEC_CONSTRUCTOR_DATA 0x2100
$#define SEC_CONSTRUCTOR_BSS 0x3100
The section has contents - a bss section could be
@code{SEC_ALLOC} | @code{SEC_HAS_CONTENTS}, a debug section could be
@code{SEC_HAS_CONTENTS}
$#define SEC_HAS_CONTENTS 0x200
An instruction to the linker not to output sections containing
this flag even if they have information which would normally be written.
$#define SEC_NEVER_LOAD 0x400
The base address of the section in the address space of the target.
$ bfd_vma vma;
The size of the section in bytes of the loaded section. This contains
a value even if the section has no contents (eg, the size of @code{.bss}).
$ bfd_size_type size;
If this section is going to be output, then this value is the
offset into the output section of the first byte in the input
section. Eg, if this was going to start at the 100th byte in the
output section, this value would be 100.
$ bfd_vma output_offset;
The output section through which to map on output.
$ struct sec *output_section;
The alignment requirement of the section, as an exponent - eg 3
aligns to 2^3 (or 8)
$ unsigned int alignment_power;
If an input section, a pointer to a vector of relocation records for
the data in this section.
$ struct reloc_cache_entry *relocation;
If an output section, a pointer to a vector of pointers to
relocation records for the data in this section.
$ struct reloc_cache_entry **orelocation;
The number of relocation records in one of the above
$ unsigned reloc_count;
Which section is it 0..nth
$ int index;
Information below is back end specific - and not always used or
updated
File position of section data
$ file_ptr filepos;
File position of relocation info
$ file_ptr rel_filepos;
File position of line data
$ file_ptr line_filepos;
Pointer to data for applications
$ PTR userdata;
$ struct lang_output_section *otheruserdata;
Attached line number information
$ alent *lineno;
Number of line number records
$ unsigned int lineno_count;
When a section is being output, this value changes as more
linenumbers are written out
$ file_ptr moving_line_filepos;
what the section number is in the target world
$ unsigned int target_index;
$ PTR used_by_bfd;
If this is a constructor section then here is a list of the
relocations created to relocate items within it.
$ struct relent_chain *constructor_chain;
The BFD which owns the section.
$ bfd *owner;
$} asection ;
*---
DESCRIPTION
Runs through the provided @var{abfd} and returns the
<<asection>> who's name matches that provided, otherwise NULL.
@xref{Sections}, for more information.
*/
/*doc*
@node section prototypes, , typedef asection, Sections
@subsection section prototypes
*/
/*proto* bfd_get_section_by_name
Runs through the provided @var{abfd} and returns the @code{asection}
who's name matches that provided, otherwise NULL. @xref{Sections}, for more information.
*; PROTO(asection *, bfd_get_section_by_name,
(bfd *abfd, CONST char *name));
*/
asection *
DEFUN(bfd_get_section_by_name,(abfd, name),
bfd *abfd AND
@ -320,21 +349,63 @@ DEFUN(bfd_get_section_by_name,(abfd, name),
}
/*proto* bfd_make_section
This function creates a new empty section called @var{name} and attaches it
to the end of the chain of sections for the BFD supplied. An attempt to
create a section with a name which is already in use, returns NULL without
changing the section chain.
/*
FUNCTION
bfd_make_section_old_way
Possible errors are:
@table @code
@item invalid_operation
If output has already started for this BFD.
@item no_memory
If obstack alloc fails.
@end table
SYNOPSIS
asection *bfd_make_section_old_way(bfd *, CONST char *name);
*; PROTO(asection *, bfd_make_section, (bfd *, CONST char *name));
DESCRIPTION
This function creates a new empty section called @var{name}
and attaches it to the end of the chain of sections for the
BFD supplied. An attempt to create a section with a name which
is already in use, returns its pointer without changing the
section chain.
It has the funny name since this is the way it used to be
before is was rewritten...
Possible errors are:
o invalid_operation
If output has already started for this BFD.
o no_memory
If obstack alloc fails.
*/
asection *
DEFUN(bfd_make_section_old_way,(abfd, name),
bfd *abfd AND
CONST char * name)
{
asection *sec = bfd_get_section_by_name(abfd, name);
if (sec == (asection *)NULL)
{
sec = bfd_make_section(abfd, name);
}
return sec;
}
/*
FUNCTION
bfd_make_section
SYNOPSIS
asection * bfd_make_section(bfd *, CONST char *name);
DESCRIPTION
This function creates a new empty section called @var{name}
and attaches it to the end of the chain of sections for the
BFD supplied. An attempt to create a section with a name which
is already in use, returns NULL without changing the section
chain.
Possible errors are:
o invalid_operation - If output has already started for this BFD.
o no_memory - If obstack alloc fails.
*/
@ -385,19 +456,23 @@ DEFUN(bfd_make_section,(abfd, name),
}
/*proto* bfd_set_section_flags
Attempts to set the attributes of the section named in the BFD
supplied to the value. Returns true on success, false on error.
Possible error returns are:
@table @code
@item invalid operation
The section cannot have one or more of the attributes requested. For
example, a .bss section in @code{a.out} may not have the
@code{SEC_HAS_CONTENTS} field set.
@end table
/*
FUNCTION
bfd_set_section_flags
SYNOPSIS
boolean bfd_set_section_flags(bfd *, asection *, flagword);
DESCRIPTION
Attempts to set the attributes of the section named in the BFD
supplied to the value. Returns true on success, false on
error. Possible error returns are:
o invalid operation
The section cannot have one or more of the attributes
requested. For example, a .bss section in <<a.out>> may not
have the <<SEC_HAS_CONTENTS>> field set.
*; PROTO(boolean, bfd_set_section_flags,
(bfd *, asection *, flagword));
*/
boolean
@ -416,27 +491,28 @@ DEFUN(bfd_set_section_flags,(abfd, section, flags),
}
/*proto* bfd_map_over_sections
Calls the provided function @var{func} for each section attached to
the BFD @var{abfd}, passing @var{obj} as an argument. The function
will be called as if by
/*
FUNCTION
bfd_map_over_sections
@example
func(abfd, the_section, obj);
@end example
SYNOPSIS
void bfd_map_over_sections(bfd *abfd, void (*func)(), PTR obj);
DESCRIPTION
Calls the provided function @var{func} for each section
attached to the BFD @var{abfd}, passing @var{obj} as an
argument. The function will be called as if by
| func(abfd, the_section, obj);
This is the prefered method for iterating over sections, an
alternative would be to use a loop:
| section *p;
| for (p = abfd->sections; p != NULL; p = p->next)
| func(abfd, p, ...)
*; PROTO(void, bfd_map_over_sections,
(bfd *abfd, void (*func)(), PTR obj));
This is the prefered method for iterating over sections, an
alternative would be to use a loop:
@example
section *p;
for (p = abfd->sections; p != NULL; p = p->next)
func(abfd, p, ...)
@end example
*/
/*VARARGS2*/
@ -457,18 +533,21 @@ DEFUN(bfd_map_over_sections,(abfd, operation, user_storage),
}
/*proto* bfd_set_section_size
Sets @var{section} to the size @var{val}. If the operation is ok, then
@code{true} is returned, else @code{false}.
/*
FUNCTION
bfd_set_section_size
Possible error returns:
@table @code
@item invalid_operation
Writing has started to the BFD, so setting the size is invalid
@end table
SYNOPSIS
boolean bfd_set_section_size(bfd *, asection *, bfd_size_type val);
DESCRIPTION
Sets @var{section} to the size @var{val}. If the operation is
ok, then <<true>> is returned, else <<false>>.
Possible error returns:
o invalid_operation
Writing has started to the BFD, so setting the size is invalid
*; PROTO(boolean, bfd_set_section_size,
(bfd *, asection *, bfd_size_type val));
*/
boolean
@ -490,27 +569,35 @@ DEFUN(bfd_set_section_size,(abfd, ptr, val),
return true;
}
/*proto* bfd_set_section_contents
Sets the contents of the section @var{section} in BFD @var{abfd} to
the data starting in memory at @var{data}. The data is written to the
output section starting at offset @var{offset} for @var{count} bytes.
/*
FUNCTION
bfd_set_section_contents
Normally @code{true} is returned, else @code{false}. Possible error
returns are:
@table @code
@item no_contents
The output section does not have the @code{SEC_HAS_CONTENTS}
attribute, so nothing can be written to it.
@item and some more too
@end table
This routine is front end to the back end function @code{_bfd_set_section_contents}.
*; PROTO(boolean, bfd_set_section_contents,
SYNOPSIS
boolean bfd_set_section_contents
(bfd *abfd,
asection *section,
PTR data,
file_ptr offset,
bfd_size_type count));
bfd_size_type count);
DESCRIPTION
Sets the contents of the section @var{section} in BFD
@var{abfd} to the data starting in memory at @var{data}. The
data is written to the output section starting at offset
@var{offset} for @var{count} bytes.
Normally <<true>> is returned, else <<false>>. Possible error
returns are:
o no_contents
The output section does not have the <<SEC_HAS_CONTENTS>>
attribute, so nothing can be written to it.
o and some more too
This routine is front end to the back end function
<<_bfd_set_section_contents>>.
*/
@ -538,25 +625,26 @@ DEFUN(bfd_set_section_contents,(abfd, section, location, offset, count),
return false;
}
/*proto* bfd_get_section_contents
This function reads data from @var{section} in BFD @var{abfd} into
memory starting at @var{location}. The data is read at an offset of
@var{offset} from the start of the input section, and is read for
@var{count} bytes.
/*
FUNCTION
bfd_get_section_contents
If the contents of a constuctor with the @code{SEC_CONSTUCTOR} flag
set are requested, then the @var{location} is filled with zeroes.
If no errors occur, @code{true} is returned, else @code{false}.
Possible errors are:
@table @code
@item unknown yet
@end table
*; PROTO(boolean, bfd_get_section_contents,
SYNOPSIS
boolean bfd_get_section_contents
(bfd *abfd, asection *section, PTR location,
file_ptr offset, bfd_size_type count));
file_ptr offset, bfd_size_type count);
DESCRIPTION
This function reads data from @var{section} in BFD @var{abfd}
into memory starting at @var{location}. The data is read at an
offset of @var{offset} from the start of the input section,
and is read for @var{count} bytes.
If the contents of a constuctor with the <<SEC_CONSTUCTOR>>
flag set are requested, then the @var{location} is filled with
zeroes. If no errors occur, <<true>> is returned, else
<<false>>.
*/